With interest rates so low does anyone use the Vanguard Intermediate-Term Tax-Exempt Fund as their emergency fund? Historically are there that big of fluctuations that it would be a problem I needed the money for an emergency?

As an Emergency Physician in Los Angeles we get many EMS notifications and patients that use the Lifeline system. I am young and only have grandparents that use Philips Lifeline but can at least testify that it works and seems to be incredibly reliable. There are various reviews online as well about...